1. Field of the Disclosure
The disclosure is directed to devices and methods for a magazine cap retention system for a firearm. In particular, the disclosure is directed to a magazine cap retention system that prevents the magazine cap from loosening during shooting and other activities.
The ability to not loosen is accomplished by using a more robust system that, for example, does not disengage during shooting. Such a system may include an extended mechanical connection. The extended mechanical connection allows components to move in one aspect but not move in other aspects. For example, the extended mechanical connection may be a circumferential “spline” tooth-form. This tooth-form has a greater length of engagement, which can be limited, so the locking features of the two components never disengage during shooting. Other implementations are contemplated.
2. Related Art
Certain shoulder firearms such as repeating shot-guns include tubular magazines secured to the forward end of a receiver. The magazine tube is commonly enclosed within a fore-end. Shotgun shells are loaded into a magazine tube and are spring biased toward the receiver so as to permit reloading after firing. The forward end of the magazine tube is closed by a threaded cap. This cap also constitutes the forward abutment for the fore-end so that a tightly threaded cap will securely maintain the fore-end stock in place.
During normal use of prior art firearms, the actions of the barrel recoil upon firing, ejection of the fired shell and subsequent reload tend to loosen the magazine cap. Without some additional mechanism, the cap can come completely off, thereby causing the spring and associated parts within the magazine tube to come apart.
Several types of systems have been used in the past to prevent loosening of the magazine cap. One prior art method of mechanical engagement includes a circular “wave” tooth-form, that is predisposed in an axial orientation as disclosed in U.S. Pat. No. 4,310,982 to Jack L. Kast, assigned to the assignee of the invention. During firearm recoil, the “spring-loaded” Magazine Spring Retainer, which engages the tooth-form in the magazine cap, may disengage the tooth-form, thereby allowing the magazine cap to rotate, and eventually become loose. This occurrence is mostly a function of the amount of engagement of the tooth-form, and the amount of recoil of the firearm.
Another technique is described in U.S. Pat. No. 2,402,086 to Leon A. Rix, assigned to the assignee of the invention, wherein the fore-end of the tube has a bushing brazed thereon provided with a circumferential series of ratchet teeth. A separate detent washer with a circumferential series of ratchet teeth is biased by the magazine spring against the inner end of the bushing so as to mesh with its ratchet teeth. The detent washer is provided with a protrusion which is intended to fit into a slot in the magazine cap so that, as the cap is tightened, the slot will engage the projection. Further tightening of the cap causes the teeth of the detent washer to engage those of the bushing until they are in fully seated meshing engagement. The cap is thus resiliently held against turning relative to the magazine tube.
Another system is the subject of U.S. Pat. No. 4,087,930 to William H. Grehl, in which the magazine spring urges two projecting prongs or fingers of a detent member at the fore-end of the magazine tube into engagement with a slotted or notched surface along the inner periphery of the magazine cap. In this system, the spring retainer is a separate element from the detent member and the former must be friction fit to the wall of the magazine tube.
In yet another prior art system, a single detent is located along the circumference of a metal frame located within the fore-end stock. The detent is biased by its own spring to engage slots along the outer periphery of the magazine cap and thus detent the latter.